To find the arctangent, or inverse tangent, of a number, we can use the php **atan()** function.

`atan(x)`

In php, we can easily use trigonometric functions from the collection of php math functions. These php math functions allow us to perform trigonometry easily.

To find the arctangent of a number, we use the php **atan()** function.

Below is the php syntax to find the inverse tangent of a number.

`atan(x)`

The input to the **atan()** function must be a float. The return value will be a float between -pi/2 and pi/2 radians.

```
echo atan(5); // 1.373400766945016
echo atan(0); // 0.0
echo atan(-3); // -1.2490457723982544
```

## Finding the Inverse Tangent of a Number in php

Arctangent is defined as the inverse of the tangent of a number.

Below, we show that if we pass a number to **tan()** and then call the php **atan()** function, we get back the same number.

```
echo atan(tan(pi()/3)); // 1.0471975511965976
echo pi()/3; // 1.0471975511965976
```

## Find Arc Tangent of the Quotient of Two Arguments with atan2() in php

php gives us the ability to find the arctangent of the quotient of two numbers, where the two numbers represents the coordinates of a point (x,y). To find the arctangent of a the quotient of two numbers, we use the **atan2()** function.

Below is the php syntax to find the inverse tangent of the quotient of two numbers.

`atan2(x)`

The inputs to the atan2() function must be floats. The return value will be a float between -pi and pi.

```
echo atan2(5,1); // 1.373400766945016
echo atan2(0,0); // 0.0
echo atan2(-3,7); // -0.40489178628508343
```

Hopefully this article has been beneficial for you to understand how to use the **atan()** function in php to find the arctangent of a number.

## Leave a Reply